> It's my understanding that the Samba folks are working on
> such a replacement. Hence, you might seek out an appropriate
> Samba mailing list to see what they might have to offer in
> this area.
Yep, what you want is Samba 4, which is currently under development. The
"released" Samba 4 may or may not use OpenLDAP, they've indicated they might
just build their own DSA. No current software will give you a drop in AD
replacement.
See the samba archives for more information.